1. Technical Field
Embodiments of the present invention are generally concerned with a plasma processing reactor chamber for processing workpieces, in which plasma is generated by inductive coupling of RF power to process gases inside the chamber.
2. Description of Related Art
Electronic devices such as integrated circuits, flat panel displays and the like, are fabricated by a series of processes, in which thin film layers are deposited on substrates and etched into desired patterns. The process steps may include plasma-enhanced reactive ion etching (RIE), plasma-enhanced chemical vapor deposition (CVD), plasma-enhanced physical vapor deposition (PVD).
Uniform distribution of etch rate or deposition rate across the entire surface of the substrate is essential for successful fabrication. Such uniformity is becoming more difficult to achieve, as substrate size is increasing and device geometry is shrinking. In particular, inductively coupled plasma sources can have two concentrically arranged coil antennas over the chamber ceiling, so that uniformity of etch rate distribution can be optimized by adjusting the different RF power levels delivered to the different coil antennas. As workpiece diameter and chamber diameter increase, we have found this approach is not adequate, as the larger size increases the difficultly of attaining the requisite process uniformity. Various sources of process non-uniformity, such as chamber design asymmetries, temperature distribution non-uniformities and gas distribution control become more important.